Swine flu could become pandemic, health officials say

A growing number of swine flu cases in Mexico and the U.S. has international health officials concerned that the aggressive virus could infect people worldwide.

The World Health Organization Saturday declared the outbreak of the previously unknown virus "a public health emergency of international concern." Accordingly, the agency advised health workers in all countries to watch closely for signs of flu-like illness and severe pneumonia.

The agency's recommendation came after an emergency committee meeting Saturday to consider raising its alert level regarding the outbreak to 6 - a pandemic - which could have led to travel advisories and additional restrictions to contain the disease. The agency's alert for the virus remains at 3, meaning "no or very limited human-to-human transmission."

World health authorities are also making sure that flu vaccines can be distributed to countries that need them.

Both the World Health Organization and the U.S. Centers for Disease Control and Prevention have been in contact with Swiss pharmaceutical giant Roche Holding Ltd., a company spokeswoman said. Roche's Tamiflu antiviral flu medicine seems effective against the virus, which is a combination of human, pig and bird flu strains.

The World Health Organization has also contacted British drugmaker GlaxoSmithKline, which manufactures Relenza, another antiviral treatment.

The Roche spokeswoman said 5 million units of Tamiflu -- 2 million of which are already with the WHO -- have been donated and are stockpiled for emergency use. She added that if requested the company would be able to speed production of the drug.

"People are taking this extremely seriously. We have a very severe situation," said Dr. Anne Schuchat, the interim deputy director for science and public health program at the CDC in Atlanta.

Speaking to reporters by telephone Saturday, Schuchat said the CDC's efforts are aimed at reducing the spread of the disease, which has killed at least 68 people in Mexico in the past month. More than 1,000 others in the Mexico City area have developed flu-like symptoms, according to media reports.

In the U.S., meanwhile, Kansas state health officials confirmed two cases of swine flu, and New York health officials said they had eight probable cases, CNN reported on Saturday.

Eight others in the U.S. -- six in California and two in Texas -- were confirmed to have come down with a similar strain of the flu found in Mexico, according to the CDC. All eight have recovered, the CDC said, with only one patient needing hospitalization.

Given that the new virus has appeared in diverse populations and in many communities, containing it is no longer feasible, Schuchat said.

"We're not at a point where we can keep this virus in just one place," she noted. "We do expect more cases and we do expect them in other communities."